This is a proposal to study the possible role of phospholipase A in experimental cell injury. The study will utilize the rat and the experimental injury will be administration of E. coli endotoxin in vivo and in vitro. Two tissues, liver and kidney will be examined. Phospholipase A activity will be assayed in whole homogenates and subcellular organelles (plasma membrane, microsomes, lysosomes and mitochondrial) in control and endotoxin treated animals. Ig an alteration of enzyme activity is observed with administration of endotoxin in vivo, then studies will be made of the effect of endotoxin in vitro. Our experimental results indicate that ischemia and anoxia result in elevations in lysophosphatides and free fatty acids; presumably by activation of phospholypases. The experimental design will include these modalities as they are common factors implicated in cell injury.